How to create a 3D screenshot

I'm trying to create a 3D version of a screenshot. Something like this:

How can I do that? I know somehow to do this in Photoshop? But I was wondering if there is a free software or online tool for this?

Answer

You got it right when you said Photoshop, and it's pretty easy, too. You have your screenshot, another one at the bottom turned 180° and erased a little plus some transparency for the reflection effect, then select both and transform with perspective and distort.

All you have to do now is play with a layer and a selection of your desired shadow colored black. Blur, eraser and stuff...

That'll be all, so if you get your hands on Photoshop, this is the way to do it.

PS: If you already have Photoshop, why not tackle this head on, rather than wasting time looking for a action on the internet or for a tool that will probably not do it exactly as you want? It's a simple process and for an experienced user it takes less than a minute. For someone with little Photoshop knowledge it will probably take 30 minutes but you will spend more trying to find a tool that generates this automatically. Just my opinion, good luck with whatever approach you may choose.